The Pūrvamīmāṁsāsūtras of Jaimini (200 B. C.) has 2700 sūtras spread over 12 chapters containing 60 subsections. The earliest and the most authoritative commentary on it is by Śabarasvāmin (100 B. C.) and is called Śābarabhāṣya.
Kumārilabhaṭṭa (8th century A. D.) wrote three works in verses on this Śābarabhāṣya, out of which the Tantra-vārttika is the second. It covers the portion 1.2 to the end of chapter 3. It is quite voluminous.